Modern vehicles are generally equipped with electronically controlled brake systems which provide functions such as brake slip control (ABS, anti-lock brake system), which prevents the wheels from locking during a braking operation, and driving dynamics control (ESC, electronic stability control) which is described, for example, in EP 0792 229 B1, which his incorporated by reference. If an unstable driving situation is identified, active braking intervention is performed, wherein the driving dynamics control means requests that braking torque be built up at one or more wheels independently of the driver and be implemented by the brake system, this stabilizing the vehicle by virtue of a deliberately introduced yaw moment.
Furthermore, motor vehicles increasingly have environment sensors with which other traffic and stationary obstacles can be detected and the positions and/or speeds of said traffic and obstacles in relation to the vehicle which is fitted with the environment sensor can be determined. Networking this environment sensor system with an electronically controlled brake system allows distance control with respect to the motor vehicle traveling in front (ACC, adaptive cruise control), emission of a warning to the driver in the event of particularly critical situations occurring, and automatic initiation of emergency braking when there is a threat of collision. In order to avoid faulty interventions, such an emergency brake assistant (EBA) must only intervene at a late stage, that is to say at the shortest possible distance from the obstacle.
When a braking request is made on account of a safety-critical driving situation, the electronic brake system has to implement said braking request as quickly as possible by building up braking torque. In the case of hydraulic brake systems, this can be achieved in that a pump builds up pressure in one or more wheel brake cylinders.
DE 199 17 904 C2, which is incorporated by reference, discloses a method for driving a pump for supplying auxiliary pressure to a vehicle brake system, in which method full power is supplied to the pump in a first phase, and said pump is operated in a cyclical mode or in a pulsed manner in a second phase. When a condition for identifying an existing increased loading is met, the cyclical mode is suppressed for a prespecifiable time, that is to say full power is supplied to the pump.
DE 10 2009 038 805 A1, which is incorporated by reference, discloses an electronic motor vehicle control device having a boost converter (DCDC converter). When a function request with a high power demand is made, the DCDC converter is switched to an active operating state in which the supply voltage for the driven load is increased in relation to the on-board voltage. Therefore, the functioning of the actuator can be ensured even at a relatively low on-board electrical system voltage. The motor vehicle control device is more costly to manufacture owing to the additional components required.